SAPPORO (Kyodo) Restaurant chain Yoshinoya D&C Co. has asked the eight Hokkaido farm co-ops that supply it with rice to ask member farmers to sign petitions seeking a resumption in U.S. beef imports, co-op officials said Tuesday.

"We are aware that there are pros and cons to this issue, so we have not forced farmers to provide signatures," a Yoshinoya official said.

Most of the rice used in Yoshinoya dishes is the Kirara 397 brand grown in Hokkaido. The company mailed a package of petition documents to the eight agricultural cooperatives in February.

Yoshinoya was a leading provider of "gyudon" bowls of beef on rice until Japan barred imports of U.S.-grown beef in late 2003 following the discovery of the first U.S. case of mad cow disease.

Some of the co-ops have decided to cooperate with Yoshinoya's request. But all of them said their policy was to leave the decision to sign to each farmer.

"We have given each farming household the freedom to decide whether to sign the petition or not," said the Pinne Agricultural Cooperative, one of the eight co-ops.

The co-op members include cattle breeders, some of whom have objected to reopening the market to U.S. beef imports. They say it might not be possible to verify the safety of such beef.